Subsurface Pipe Dimension and Position Indicating Device

ABSTRACT

A sensing system provides real time information as to the location of a stand in a tubular string at a predetermined elevation such as where the rams are located. This allows a determination of whether the upsets are aligned with the ramps or whether the stand is aligned with the rams in a manner that the rams will close on the tubular between the end upsets. The surrounding pipe has circumferentially spaced transmitters and receivers to allow a determination of the outer dimension of the pipe and to transmit such information to the surface by conductors or other means. The position of a tubular in an open hole can also be determined by sending a signal from the tubular to the open hole and back to the tubular. Different signal regimes are contemplated as well as power supply options.

FIELD OF THE INVENTION

The field of the invention is measuring systems that sense the outer dimension of a component of a tubular string or the shape of a tool or other string component at a specific location in a borehole and more particularly devices that provide such information in real time without reducing the drift dimension of the supporting pipe for the sensing and transmission equipment.

BACKGROUND OF THE INVENTION

In certain situations it is helpful to know the position of the string in the hole at a specific elevation and more particularly where the upsets are positioned. In the case of a blowout preventer set of rams it is advantageous to close the rams on a tubular string component between the upset ends rather than on the upset portions. In the past approximations were made based on footage run into the hole however there were many uncertainties as to the pipe position with respect to the placements of the upsets with regard to the plane in which the rams were to be operated. What was needed was a way to gauge the position of a stand in a string with respect to the plane of operation of the rams without decreasing drift dimension of the surrounding tubular. In other instances the position of the string with respect to the surrounding tubular may need to be known. Alternatively, the position of a string with respect to a surrounding open hole can be determined with variations of the present invention.

Signal transmitters and sensors for the reflected signals are provided in circumferentially spaced locations with power being supplied locally such as from a battery or remotely by wires or other conductors that can extend from the zone of interest to a convenient surface location. The orientation of the transmitters and sensors can be inwardly directed to sense the dimension of a stand of pipe inside a surrounding tubular or the orientation can be outwardly oriented so as to sense the position of a tubular with respect to a surrounding open hole for example. The transmission and sensing equipment can be preinstalled on the surrounding pipe or can optionally be installed on the inner pipe to direct a signal to the surrounding outer pipe for reflection back to the inner pipe. Sound, vibration, pressure pulses or RF among other signal formats are contemplated. Measurement of cylindrical as well as other shapes are contemplated. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawing with the understanding that the full scope of the invention is to be determined from the appended claims.

SUMMARY OF THE INVENTION

A sensing system provides real time information as to the location of a stand in a tubular string at a predetermined elevation such as where the rams are located. This allows a determination of whether the upsets are aligned with the ramps or whether the stand is aligned with the rams in a manner that the rams will close on the tubular between the end upsets. The surrounding pipe has circumferentially spaced transmitters and receivers to allow a determination of the outer dimension of the pipe and to transmit such information to the surface by conductors or other means. Measurement of other or irregular shapes such as of tools is also contemplated. The position of a tubular in an open hole can also be determined by sending a signal from the tubular to the open hole and back to the tubular. Different signal regimes are contemplated as well as power supply options.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE illustrates an elevation view of the sensor and transmitter on a surrounding tubular to measure the dimension of a stand of an inner string at a predetermined location.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The FIGURE shows a tubular string 10 which supports a schematically illustrated blowout preventer 12 that has sliding rams that are not shown. The blowout preventer is of a type well known in the art with opposed rams designed to encircle the string 14 preferably at a location on a stand of tubular 16 between upsets 18 and 20. The problem in the past has been the lack of specific knowledge that the portion of tubular 16 between the upsets 18 and 20 is in general alignment with the rams of the blowout preventer 12.

A signal transmitter array 22 is preferably mounted in a single place and circumferentially evenly spaced although an uneven spacing is also contemplated. A signal 24 goes out to the tubular 16 and is reflected back 26 to a respective signal receiver 28 into a multipurpose conductor 30 for transmission of the data to a surface location. Conductor 30 can also supply power to array 22 and receivers 28 or as an alternative a local power supply such as batteries can be used. In either event the transmitters 22 and receivers 28 are preferably mounted to the surrounding tubular string 10 with an orientation toward the tubular string 14. The reverse arrangement is also contemplated with the transmitters 22 and receivers 28 located on string 14 sending a signal and receiving a reflected signal from the surrounding tubular 10.

Other alternatives are contemplated such as location of the transmitters 22 and receivers 28 on a tubular string such as 10 when that string is run into open hole as a way of either determining the open hole shape, which can be irregular, at a given location or/and the position of the string 10 with regard to the shape of the hole. While the open hole shape can be irregular especially in poorly consolidated formations, in more consolidated formation the hole dimension is more reliably constant and data on the position of the string within the hole at a particular location will be more reliable.

Different signal types are contemplated such as pressure pulses, RF, acoustic or vibration to name a few examples. With the use of multiple circumferentially spaced transmitters 22 and receivers 28 accurate measure of the dimension of the string 14 can be obtained even if the string 14 is sitting eccentrically in the surrounding tubular 10. Using this technique allows real time knowledge of the alignment of the string 14 so that the smaller dimension between upsets 18 and 20 is in general alignment with the blowout preventer rams.

Those skilled in the art will appreciate that the described system can detect pipe outer dimension as well as outer dimension of irregular shapes such as well tools, with the aid of a local or surface mounted processor as being present in a given depth in a borehole with accuracy and in a real time manner. Using known internal dimension of the surrounding pipe and distance computed from the surrounding pipe to the internal pipe or tool from spaced apart locations, the processor can then confirm that the smaller dimension of a stand of pipe is in alignment with the rams, in one proposed application. In that way the string can be manipulated so that the rams close on a desired tubular dimension between upsets as it is designed to do. Alternatively, the presence and shape of a specific tool at a specific location can also be determined. The inaccuracies of the previous methods are eliminated as is the possibility of human error. In still other applications the position of the sting or a tool on the string with respect to a surrounding pipe such as in a deviated borehole can also be computed apart from the determination of the external pipe dimensions. The transmitters 22 and receivers 28 can be on the outer pipe as shown in the FIGURE or on the surrounding pipe and in either case should be configured to not reduce the drift dimension of the surrounding tubular. This can be accomplished with use of a recess or a wide spot in the line. Alternatively the transmitters 22 and receivers 28 can be on a tubular exterior facing open hole to detect the pipe position or the position of a tool on the pipe with respect to the open hole.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: 

I claim:
 1. A sensing system for detecting the outer dimensions of a tubular or a tool at a specific location or the position of a tubular or tool in cased or open hole, comprising: a plurality of spaced signal transmitters and signal sensors to detect the spacing of a stand of pipe from the cased or open hole at a predetermined depth or the shape of a tool at a predetermined depth; a processor to compute the outer dimensions of said stand of pipe or said tool using data from said signal transmitters.
 2. The system of claim 1, wherein: said transmitters and sensors are in the same plane.
 3. The system of claim 1, wherein: said transmitters send one of an acoustic, vibration, pressure pulse or radio frequency signals that are reflected from said stand of pipe to said sensors.
 4. The system of claim 1, further comprising: a blowout preventer in the cased hole; said processor indicating a small diameter between upsets or said tool as aligned with rams on said blowout preventer to allow said rams to close against said stand on said small diameter or to signal that said stand of pipe needs to be moved to prevent closing said rams on said tool.
 5. The system of claim 1, wherein: said sensors and transmitters are located in casing defining the cased hole.
 6. The system of claim 1, wherein: said sensors and transmitters are located on the stand of tubular.
 7. The system of claim 1, wherein: said sensors and transmitters do not reduce the drift dimension of casing defining the cased hole.
 8. The system of claim 1, wherein: said transmitters send a signal from said stand of pipe toward the open hole to sense position of said stand of pipe with respect to the open hole.
 9. The system of claim 1, wherein: said sensors and transmitters are circumferentially spaced, evenly or unevenly.
 10. The system of claim 1, wherein: said sensors and transmitters are powered locally or from a surface location of a borehole.
 11. A method of positioning a portion of a stand of a string between upsets in alignment with rams of a blowout preventer, comprising: sensing the distance from an outer surface of a stand of a tubular string to a wall of a surrounding tubular from a plurality of circumferentially spaced locations; computing the outer dimension of the tubular or of a tool from said sensing; repositioning said stand of a tubular before operating said rams if the outer dimension indicated is not the smallest known outer dimension of said stand located between opposed upsets or if a tool is aligned with said rams.
 12. The method of claim 11, comprising: performing said sensing in a common plane adjacent said rams.
 13. The method of claim 11, comprising: equally or unequally spacing pairs of transmitters and respective sensors that send and receive a signal reflected from said stand of a tubular.
 14. The method of claim 13, comprising: connecting said sensors to a processor to compute the outer dimension of the stand of tubular to allow real time communication of said outer dimension to a remote location.
 15. The method of claim 14, comprising: locating said processor near said rams or at a remote location.
 16. The method of claim 11, comprising: using transmitters and sensors in pairs to feed data to a processor to compute the outer dimension of the stand of pipe; powering said sensors and transmitters locally or from a remote location.
 17. The method of claim 11, comprising: using as a signal to be sensed one of acoustic, vibration, pressure pulse or radio frequency.
 18. The method of claim 11, comprising: performing said sensing with pairs of signal transmitters and sensors located on said string or said surrounding tubular.
 19. The method of claim 11, comprising: determining the outer dimension of the stand op pipe even when the stand is not centered within the surrounding tubular. 